| Message ID | 1282020249-8807-2-git-send-email-vapier@gentoo.org |
|---|---|
| State | Accepted |
| Headers | show |
On Tue, 17 Aug 2010 00:44:07 -0400 Mike Frysinger <vapier@gentoo.org> wrote: > If we don't do any of this, working with the RTC causes ~5 second delays > from time to time after waking up due to the write completion interrupt > never firing. > > Reported-by: Michael Dean <mdean@aeronix.com> > Reported-by: Michael Hennerich <michael.hennerich@analog.com> > Signed-off-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Alessandro Zummo <a.zummo@towertech.it>
diff --git a/drivers/rtc/rtc-bfin.c b/drivers/rtc/rtc-bfin.c index 65facfb..d4fb82d 100644 --- a/drivers/rtc/rtc-bfin.c +++ b/drivers/rtc/rtc-bfin.c @@ -435,8 +435,17 @@ static int bfin_rtc_resume(struct platform_device *pdev) { if (device_may_wakeup(&pdev->dev)) disable_irq_wake(IRQ_RTC); - else - bfin_write_RTC_ISTAT(-1); + + /* + * Since only some of the RTC bits are maintained externally in the + * Vbat domain, we need to wait for the RTC MMRs to be synced into + * the core after waking up. This happens every RTC 1HZ. Once that + * has happened, we can go ahead and re-enable the important write + * complete interrupt event. + */ + while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_SEC)) + continue; + bfin_rtc_int_set(RTC_ISTAT_WRITE_COMPLETE); return 0; }
Much (but not all) of the RTC state is kept in the RTC peripheral which has its own power domain. Periodically (1 HZ), that state is synced from one power domain to the other (peripheral->core). When we are resuming, we need to wait for the sync to occur so that we don't get a mismatch of reading undefined state in the rest of the driver. Further, once the externally maintained bits have been synced back into the core, we then need to restore the bits maintained in the core. In our particular case, that is just the write completion interrupt bit. If we don't do any of this, working with the RTC causes ~5 second delays from time to time after waking up due to the write completion interrupt never firing. Reported-by: Michael Dean <mdean@aeronix.com> Reported-by: Michael Hennerich <michael.hennerich@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> --- drivers/rtc/rtc-bfin.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-)